Unfold the pastry sheet on a lightly floured surface. Roll the pastry sheet into a 10-inch square. Cut into 4 (2 1/2-inch) strips. Cut each strip into 6 (3x3x3-inch) triangles. Discard any remaining pastry. Press the pastry triangles into the bottoms and up the sides of 24 (1 1/2-inch) mini muffin-pan cups.

Bake for 7 minutes.

Cut slits in the tops of the tomatoes and scoop out the seeds. Spoon about 1 1/2 teaspoons cheese mixture into each tomato. Place the tomatoes in the center of the warm pastries and press down lightly.